Explainer
The PSTN switch-off: what happens to your phone lines
Analogue phone lines stop working on 31 January 2027. Anything running on one - desk phones, alarms, lifts, card machines - has to move to a digital connection before then.
By Claire Donnelly · Last reviewed 11 August 2026 · 4 min read
The short version
- The deadline is 31 January 2027, and Openreach says there will be no further delays
- It is not only phones - older ADSL and FTTC broadband ride on the same copper
- Alarms, lifts, door entry and card machines often sit on a line nobody remembers
- Copper line rental is rising steeply through 2026, so waiting has a price now
- Start by listing every line you pay for and finding what is plugged into it
What is actually being switched off
The PSTN is the public switched telephone network: the copper phone system that has carried UK calls for over a century. Openreach is retiring it, along with ISDN, the digital version most older office phone systems use.
The confirmed date is 31 January 2027, and Openreach has been clear that this one is locked. In most areas you can no longer order or change a copper service anyway, so the migration is already happening whether or not a business has planned for it.
The part that catches people out is that this is not only about phones. Older broadband – ADSL, and FTTC, which still uses copper for the final stretch to your building – depends on the same network. A business that thinks it has no phone line to worry about may still have a broadband service that does.
Openreach reported in February 2026 that around 2.8 million lines still needed to migrate, more than half a million of them serving business premises. A good number of those belong to businesses that do not yet know they are affected.
Things that quietly depend on a phone line
- Intruder and fire alarm signalling to a monitoring centre
- Lift emergency phones, which are usually a legal requirement
- Door entry and gate intercoms
- Card payment terminals, particularly older countertop models
- Franking machines and any remaining fax
- Some CCTV and building management systems
- Telecare and personal alarms, in care settings or staff accommodation
What replaces it, and what genuinely changes
Calls move to VoIP, which carries them over your internet connection instead of a dedicated copper pair. For most businesses the day-to-day experience is the same or better: the same numbers, and calls that follow people to a mobile or laptop.
Two real changes are worth planning for.
Your phones now depend on your internet connection. If the broadband is unreliable, the phones become unreliable. Connectivity that was merely annoying when it wobbled becomes something calls depend on.
Digital lines need power at your end. An old analogue phone drew its power from the exchange and kept working in a power cut. A VoIP handset does not. If you need to make calls during a power failure – and any lift phone or alarm certainly does – that needs deciding on purpose, usually with battery backup or a mobile fallback.
Where to start
Begin with an audit rather than a purchase. Find every line the business pays for, including the ones on old invoices nobody reads, and physically trace what is plugged into each. The forgotten line in a riser cupboard connected to the fire alarm is the one that causes a problem in February 2027.
Then check with each equipment supplier what their kit needs. Alarm and lift providers have migration paths, often a mobile or IP signalling module, and those need booking rather than buying off a shelf. Openreach also offers free testing at its labs for businesses unsure whether a device will survive the change.
Only after that does the phone system itself matter, and by then you will know what your connection has to support.
What happens if nothing is done
The line stops. There is no grace period on 31 January 2027 and no way to keep an analogue service running past it.
For a business whose phones are the only thing affected, that is a bad week. For one whose fire alarm signalling, lift phone or card terminal quietly used the same technology, it is considerably worse – and those are exactly the things that are nobody’s obvious responsibility until they fail.
Common questions
Will we keep our existing phone numbers?
Yes. Numbers port across to a digital service, including long-standing local ones. It is worth starting early, because porting is the part of a move most likely to need chasing.
We are already on fibre - are we fine?
Probably for broadband, but check your phones separately. Plenty of businesses have full-fibre internet and a separate analogue line still running an alarm or a lift phone, billed quietly on a different account.
What about our lift emergency phone?
It needs a migration plan and it should be near the top of your list. Lift emergency communication is a safety requirement, so speak to your lift maintenance company rather than assuming the phone provider has it covered.
Is this the same as the copper broadband switch-off?
They are part of the same retirement programme. The copper network carries both, so ADSL and FTTC services are being withdrawn on the same timetable as the phone lines.
Can we just use mobiles instead?
Some very small businesses do, and it is a legitimate choice. It works less well when you need a main number answered by whoever is free, call recording, or a number that outlives whoever currently carries the phone.
Written by Claire Donnelly
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